The present technique relates to control devices, storage devices, LSIs, and recording compensation methods for detecting patterns that causes nonlinearity on the basis of the presence or absence of magnetization inversion and performing recording compensation in accordance with the patterns.
With the development of high-density magnetic recording/reproducing apparatuses and the increase in data transmission speed, nonlinear transition shift (NLTS) occurs in magnetic heads, recording media, and recording/reproduction transmission systems. Recording compensation techniques for reducing such NLTS are known. In a recording compensation technique, write pre-compensation, patterns which cause nonlinearity, such as dibit, tribit, and 2T are detected. And a recording compensation is performed in accordance with the detected patterns.
In a recording compensation technique, NRZ (non-return-to-zero) code representing data code to be recorded on a medium in the form of levels is measured. The NRZ code is then converted into the NRZI (non-return-to-zero inverted) format representing the recording code in accordance with the inversion of levels. From the NRZI code, a pattern such as dibit, tribit, or 2T that causes nonlinearity is detected. For example, when magnetization inversion occurs, NRZI bit values of two preceding bits are detected. When the detected NRZI bit values are “011”, the pattern is defined as “dibit”. When the NRZI bit values are “111”, the pattern is defined as “tribit”. When the NRZI values are “101”, the pattern is defined as “2T”. Then recording compensation is performed using recording compensation values corresponding to these patterns. Note that in NRZI coding in this example, “0” indicates the absence of magnetization inversion, and “1” indicates the presence of magnetization inversion.
Techniques of the related art are disclosed in Japanese Laid-open Patent Publication No. 07-6306 and Japanese Laid-open Patent Publication No. 2000-20903.